Xliberater

Hello all, I have recently had an issue with the headlights on the 81. When I turn on the high beams all four of my headlights go out, including the low beams. The high beam indicator on the dash DOES come on. The low beams do work on their normal setting.

So far I have
-Replaced all 4 headlights with new ones
-Checked the grounds on the radiator support

The problem has not gone away. I have also removed the headlight/ dash light switch. All the contacts are clean and the reostat operates smoothly (This one is not original and has been replaced by a previous owner).

I am afraid that tearing into the steering column may be my next step to replace the high beam/turn signal switch.

Any help would be much appreciated

Xliberater

Bump, I checked for continuity in the switch and it is working fine. I also traced the headlight wire harness from the firewall to the headlights and couldnt find any breaks or damaged wires.

Raphiki

Sounds like a switch problem. This was posted back in 2010 by ....Roger:

Does the high beam indicator in the dash come on ?
When in high beam position check the green wire for power, if it has no power then replace the switch.
If the green has power its "possible" all 4 of your high beam filaments are burn out.

Xliberater

I thought the green wire was for the dash lights? My dash lights work at all the settings though, just my headlights are having issues.

SIXFOOTER

The Green is High beam, Tan is low beam.
Sounds like your getting power through the dimmer switch if the high beam indicator comes on. Might be a bad connection in the main harness bulkhead connector

Ray384

Check the connectors on the drivers side lights. Had a problem like this on my '80. The drivers side connectors were corroded very bad and loose, causing the brights to not work, low beams worked fine. Changed all 4 connectors and they now work great.

81corvettevortec

Having the exact same issue. I'll let you know if I find a solution.

Xliberater

Thanks for the help so far, that wiring diagram makes it a lot easier for me I bypassed the light switch by jumping the red to yellow wire and that didnt fix it so the problem is somewhere between the dimmer switch and headlights

I went out this morning and checked for voltage at the light green wire at each of the headlight connections and couldnt get any voltage. I DO get voltage at the tan wires when the low beams are on. I also used a jumper wire at the dimmer switch connector between the yellow and light green wire but it didnt solve the problem. The low beams do work when I jump the yellow to tan wire. I think the issue is somewhere in the wiring in the engine bay. When I run a wire from the battery to the driver side low beam headlight (green wire terminal) all the headlights turn on like they should.

Is there an easy way to test the bulkhead connection at the firewall? Im not sure where else to check

Update:I made a tiny incision in the high beam green wire near the alternator and used a test light to check for power, i am not getting power there either. I am almost positive that it is the bulkhead connection but it does not look like its easy to get to

Iceaxe

I had a similar issue on a 1970. It was the floor mounted dimmer switch.

Xliberater

I bypassed the switch by using a jumper wire and it didnt fix it. unfortunately the dimmer switch is mounted in the steering column unlike earlier c3's and is not easy to get to.

Raphiki

Sounds like it has to be a break at the firewall.

Xliberater

FIXED! Thanks for the help, I figured I would follow up with the solution in case anyone in the future may have a similar issue. Definitely check your bulkhead connector before throwing parts at the problem.

The rain finally decided to let up so I went out and pulled the main bulkhead connector at the firewall. I thought it would be a major PITA to remove but it only took one bolt on the engine side to and it came right out. Removing the fender grill on the side of the car made it easier to access the plug. I forgot to take pics but the entire plug was covered in 34 years of dirt and grime. I used some electrical cleaner and a metal brush the clean the contacts and applied a fresh coat of dielectric grease to the connections. After about an hour I had everything back together and tested the high beams. They worked!

Now I can feel a little safer driving at night